Engine starter gearing and control



Nov. 30, 1948. J. E. BUXTON 2,455,328

ENGINE STARTER GEARING AND CONTROL Filed Sept. 2, 1947 WWW ' INVENTOR. 140m 61,

A omy Patented Nov. 30, 1948 ENGINE STARTER GEARING AND CONTROL James E. Buxton, Elmira, N. Y., assignor to Bendix Aviation Corporation, a corporation or Delaware Application September 2, 1947, Serial No. 771,725

. Claims. (01. 290-38) The present invention relates to engine starter I gearing and more particularly to that type of starter drive which automatically connects the starting motor to the engine when the starting motor is energized, and maintains such connection until the starting motor is deenergized.

It is an object of the present invention to provide a novel engine starter drive of the stated type which is efllcient and reliable in operation while being simple and inexpensive in construction. 1

It is another object to provide such a device in which the starting switch actuates a latch which holds the driving pinion in mesh with an engine 7 gear.

It is another object to provide such a device including an overrunning clutch between the starting motor and driving pinion.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing in which:

Fig. 1 is a side elevation, partly broken away and in section, of an engine starter constituting a, preferred form of the invention, the parts being shown in idle position; and a Fig. 2 is a similar view showing the parts in positions assumed when the engine -has fired An outer barrel member i5 is arranged to surround and enclose the drive and is provided at its inner end with inturned flange I6 which is arranged to engage the end of the screw shaft 6, to thus limit the longitudinal movement of the drive in the meshing direction. The outer barrel I! has a flange ll at its outer end'which forms a stop for the driven overrunning clutch member 9, a split spring ring i8 being interposed there-between to normally maintain the clutch members 8, 9 yieldingly in engagement. An antidrift spring I 9 is interposed between the flange iii of barrel i5 and the screw shaft 5. Y

Means for energizing the starting motor are provided comprising a battery 2i grounded at 22 and connected by a lead 23 to one terminal 24 of a magnetic starting switch 25. The opposite terminal 28 of the switch is connected by a lead 2l-to the starting motor which is grounded as indicated at 28 to complete the starting circuit. Switch l5 comprises a bridging contact 29 actuated by a magnetic plunger 3L and arranged to connect contacts 24, 26 when the plunger 3i is and caused the pinion to overrun the starting motor;

In Fig. 1 there is illustrated a starting motor having an armature shaft 2 which is extended and mounted at its outer end in an outboard housing I attached to the motor casing. A pinion 4 is slidably mounted on the extended portion oi! the armature shaft 2 for movement into and out of mesh with a, member such as a gear 5 of the engine to be started.

Means for actuating the pinion 4 from the motor shaft! is provided comprising a screw shaft 6 fixed to the motor shaft as by means of a cross pin i. A- driving overrunning clutch member 8 is slidably Journalled on the motor shaft 2 in position to cooperate with a driven overrunning clutch member 8 which is fixed as indicated at H to the pinion 4. A flanged control nut i2 is threaded On the screw shaft 4, and a yielding driving member i3 of elastically deformable material is mounted at one end of the control nut and at its other end bears against the driving clutch member 8 so as to form a yielding torsional and compressive connection therebetween. A barrel member I4 is arranged to surround the control nut l2, elastic member I! and driving clutch member I and hold the elastic member initially compressed between the nut and clutch member.

moved by energizatlon of a solenoid 32. under the control of the operator for energizing the solenoid are provided comprising a manual switch 33 connected by a, lead 34 to the battery lead 23, and by a lead 35 to one terminal of the solenoid, the opposite terminal of the solenoid being grounded at 36.

Means for holding the pinion 4 in mesh with the engine gear 5 as long as the starting motor is energized is provided comprising a lever 31 pivoted at 38 on the outboard extension 3 of the motor frame and having a yoke or fork member 39 at its lower end cooperating with a channel member or collar 4i fixed on the outer barrel i5 of the drive as by means of a lock ring 42 whereby longitudinal movement of the barrel swings the lever 31 on its pivot 38.

The upper end of the lever extends into proximity to a latch member 43 pivoted at 44 to an extension 45 of the switch plunger 3i. A spring 46 mounted on said extension 45 bears on the latch 43 so as to yieldingly press it toward the end of the level 31. Latch 43 is provided with a lateral projection such as a pin 41 arranged to cooperate with a beveled cam surface 48 formed on the housing extension 3 whereby when the magnetic switch 25 is opened, the latch 43 is cammed upward out of the path of the end of lever 31. A spring 43 is provided in the magnetic switch for holding the-switch open with the latch 43 so retracted.

In operation, starting with the parts in the positions illustrated in Fig. 1 closure oi. the man- Means ing the nut to the right, which movement is,

transmitted through the elastic member l3 and clutch members 8, 9, to the pinion 4 thus moving it into mesh with the engine gear 5. When the longitudinal movement 01' the pinion is arrested by the engagement of the flange ie of the outer barrel member l5 against the end of the screw shaft 6, the pinion 4 is constrained to rotate and thus crank the engine.

Closure of the magnetic switch 25 causes the latch member 48 to be moved down into'the path of the upp r end of lever 31, and the longitudinal movement of the barrel it causes the lever 87 to swing countereclockwise until the upper end thereof passes under the end of the latch 53 and is engaged thereby as shown in Fig. 2.

When the engine fires, the acceleration of the pinion d by the engine gear causes it to overrun the starting motor, whereby the control nut i2 overruns the screw shaft 6 sufficiently to allow the overrunning clutch members 8, 9 to disengage. Further backward movement of the parts of the drive is prevented however, by the action 01' the latch 33 in retaining the lever ill in its shifted position as shown in Fig. 2. If the engine fails to remain self-operative. as soon as the speed of the engine gear 5 falls below the corresponding speed of the starting motor, the drive will re-engage and cranking will be resumed.

When the enginehas been successfully started, the operator opens the manual switch 33, whereupon the magnetic switch 25 opens and deenergizes the starting motor while the latch releases the lever ill and is cammed out of the path of said lever as shown in Fig. l. The torque transmitted to the control nut [122 from the pinion t then causes the control nut to thread itself bacls to idle position on the screw shaft ii whereby-the drive is demeshed and retained in normal position by the anti-drift spring 99.

Although but one embodiment of the invention has been shown and described in detail, it will be understood that other embodiments are possible and that various changes may be made in the design and arrangement of the parts without departing from the spirit of the invention.

I claim:

1. In an engine starter drive a starting motor, means for energizing the starting motor including a magnetic starting switch having a reciproeable plunger, a power shaft rotated by the starting motor, a pinion slidably journalled thereon for movement into and out oi mesh with a gear of an engine to be startedmeana for actuating the pinion from the power shalt including a control nut having a threaded connection to the power shaft, 8. yielding driving connection from the control nut to the pinion including an overrunning clutch; a pivoted yoke member connected to the barrel so as to swing about its pivot as the pinion moves into and. out of mesh with the engine gear, and a latch member connected to the switch plunger and arranged to engage and hold the yoke member, barrel and pinion in meshing position when the starting switch is closed.

2. An engine starter drive as set forth in claim 1 including further, means for releasing the latch from the yoke member when the starting switch is opened. I!

3. In an engine starter drive a power shaft. a pinion slidably journalled thereon for movement into and out of mesh with a gear of an engine to be started, means for actuating the pinion by rotation of the power shaft including a screw shaft fixed on the power shaft. a control nut threaded on the screw shaft, and a yielding driving connection between the control nut and pinion; means including a barrel member forming an abutment for the pinion in its driving position, a pivoted; lever connected to the barrel member for swinging movement as the barrel member moves into and out of driving position,

a latch member for holding the lever, barrel and pinion in driving position, and means for moving the latch into and out of operative position.

4. An engine starter drive as set forth in claim 3 in which the yielding driving connection ber tween the control nut and pinion includes an overrunning clutch.

5. An engine starter drive as set forth in claim 3' in which the latch moving means includes means for controlling the actuation of the power shaft.

JAMES E. .BUXTON.

CIETED The following references are of record in the file of this. patent:

UNITED STATES PATENTS 

